The effects of diabetes self-management programs on clinical and patient reported outcomes in older adults: a systematic review and meta-analysis

Objectives With diabetes self-management continuing to become more complex for older adults, self-management programs have been shown to support this population in meeting their multifaceted medical needs. Building on our previous systematic review and meta-analysis, we aimed to update the literature on the effectiveness of diabetes self-management programs and investigate the impact of specific self-management interventions on clinical and patient-reported outcomes. Methods We updated our literature search in the following databases: Medline, EMBASE, PsychINFO, CINAHL and Cochrane Database of Randomized Controlled Trials from November 2013 to July 2023 for studies that may fit our inclusion criteria. Two independent reviewers screened and extracted data from the included group of studies. Results A total of 17 studies with 21 comparison arms met the inclusion criteria, totalling 5976 older adults (3510 individuals randomized to self-management programming and 2466 to usual care). The pooled effectiveness of diabetes self-management programs in older adults on glycemic control (hemoglobin A1C) was a reduction of -0.32 (95% CI -0.44, -0.19). Specifically, the most effective approach on glycemic control (A1C) was the use of feedback (-0.52%; 95% CI -0.68, -0.36). Overall, self-management programs improved behaviour change outcomes, with feedback interventions being most effective (standardized mean difference [SMD] 0.91; 95% CI 0.39, 1.43). The effect of self-management programs on body mass index, weight and lipids were statistically and clinically significant. Conclusions The evidence for diabetes self-management programs for older adults demonstrates a small but clinically meaningful reduction in A1C, improvement in patient-reported outcomes (behaviour, self-efficacy, knowledge), and other clinical outcomes (BMI, weight and lipids). The specific strategy used in diabetes self-management programs for older adults should be considered to achieve optimal results on outcomes.


Introduction
It is estimated that 1 in every 5 people between the ages of 65-99 years old, or 136 million people, live with diabetes worldwide (1).This number is projected to rise to 276 million by 2045 (1).As society ages, the healthcare burdens associated with diabetes in older adults will grow significantly (1,2).This is in part due to this population managing comorbidities in addition to diabetes, including frailty, cognitive impairment, functional disability, and vascular complications, among others (2)(3)(4)(5).
The vascular and non-vascular comorbidities that are often paired with diabetes in older adults present a unique set of challenges for this population to overcome when managing their condition (2).Older adults experiencing multimorbidity utilize health services more often (6,7), experience poorer diabetes outcomes, and have a reduced quality of life due to their complex medical management (5).Social isolation and insufficient diabetesrelated knowledge can lead to a decrease in performing selfmanagement behaviours for this population, making them vulnerable to diabetes-related complications and premature mortality (4,5,8,9).
Recent clinical practice guidelines emphasize the importance of individualized care plans to support diabetes management for older adults (10).As this population includes a spectrum of individuals ranging from clinically stable to functionally dependent or near the end of life, the approach to disease management must be personalized (10,11).Social, functional, cognitive, medical, and psychological factors should be assessed to provide a framework for creating an individualized care plan (11).Overtreatment is a common occurrence for older adults, leading to an increased burden of managing diabetes (11) and may contribute to the negative feelings older adults experience towards self-care behaviours (8).Strategies including a simplified pharmacotherapy regimen and a more liberalized A1C target can be used to prevent hypoglycemia for older adults living with multiple comorbidities (10, 11).Self-management education and support for older adults is also an important component of diabetes care (10).Strategies to best address self-management and diabetes education for this population are warranted.
Since the completion of our previous systematic review (12), new literature has emerged on diabetes self-management education and support for older adults.In particular, the complexity of diabetes management for older adults elicits an investigation into the impact of these interventions on patient-reported outcomes such as quality of life, behaviour change, diabetes-related distress, diabetes knowledge, and self-efficacy.We aim to apply the same methodological approach as our previous review to examine more recent publications and determine the most effective diabetes selfmanagement education or support strategies in older adults, as measured by glycemic control, metabolic outcomes, and patientreported outcomes.

Conceptual model
Aligning with the conceptual model applied to our previous review (12), the framework by Chodosh et al. (13) was used to describe self-management programs through five categories: tailoring; group setting; feedback; psychological emphasis; and medical care.Studies were characterized using the five elements based on the most dominant characteristic with the assumption that the outcomes are associated with that study characteristic.

Search strategy
Relevant biomedical databases, including Medline, EMBASE, PsychINFO, CINAHL, and Cochrane Database of Randomized Controlled Trials were searched from November 2013 to July 2023 by applying the previous search strategy developed in consultation with a medical research librarian (12).Please refer to Supplementary Table 1 for an overview of our search strategy.References from relevant guidelines, systematic reviews, and metaanalyses were also examined for relevant publications.The PRISMA checklist for systematic reviews was followed throughout the completion of our review (Supplementary Table 2).

Study selection and quality appraisal
The eligibility criteria from our previous review were applied to assess all citations (12).Briefly, the inclusion criteria consisted of peer-reviewed literature, written in English, and (1) was a randomized, controlled trial; (2) included a population of older adults ≥ 65 years of age that live with Type 2 diabetes; and (3) report the differential effect of self-management support strategy or education on glycated hemoglobin A1C (HbA1c), metabolic outcomes (fasting blood glucose, body mass index [BMI], weight, lipids, blood pressure), or patient-reported outcomes (quality of life, behaviour change, diabetes-related distress, diabetes knowledge, self-efficacy).Publications were excluded if: (1) data was reported on subjects without diabetes, < 65 years of age; (2) the selfmanagement education intervention included testing new or combination oral anti-diabetic agents; (3) no statement of informed consent being obtained was included.
Three research team members (PA, MJ, SK) reviewed citations independently at the title and abstract and full-text levels.Quality assessment and data extraction were completed by three independent team members (PA, DFL, MJ).Disagreements at the full text, data extraction, and quality assessment levels were resolved through discussion between team members.Data extraction was completed using standardized forms and included information on objectives, demographics, self-management interventions, and outcomes for each publication.Quality appraisal was completed using Cochrane's risk of bias tool (14), and studies were ranked based on having a low, unclear, or high risk of bias.

Data analysis
All data analyses were planned a priori.A meta-analysis was used to combine the results across studies by outcome using the published continuous data from included studies.Specifically, we used the change from baseline to immediate post-treatment or follow-up data (mean change score, standard deviation of mean change score) for both intervention and control groups.In the studies where a measure of variance was reported as confidence intervals, standard error or p-values, we used Cochranerecommended methods to convert to standard deviation (15).We used a multi-level meta-analytical approach (where applicable) to account for statistical dependence i.e., dependency in effect sizes introduced either by comparison of multiple intervention arms within a study to a common control group or by multiple outcome measures or sub-outcome measures of a primary outcome of interest within a study (such as various measures of patientreported outcomes) (16)(17)(18).The statistical heterogeneity I 2 statistic was also estimated in the context of a multi-level metaanalytical approach i.e., within-cluster heterogeneity (multiple arms from the same study) and between-cluster heterogeneity (effect sizes across studies).Overall I 2 for each summary effect size was estimated to represent the heterogeneity not attributable to sample error and is the sum of within-cluster and between-cluster heterogeneity (19).
The summary measures of effect were generated as mean difference (MD) and standardized mean difference (SMD).The units of measurement for clinical outcomes such as weight, lipid profile measures, and blood glucose were converted into the same standard units (mmol/L for lipid outcomes and glucose, and kg for weight) before input into metanalysis.The SMD was used as a summary statistic for PROMs because the studies in this systematic review often assessed the same outcome using different outcome measures or tools.Given this, it was necessary to standardize the results of the studies before they could be compared across studies or combined in a quantitative synthesis.The SMD is interpreted based on its magnitude according to Cohen d recommended thresholds (~0.2=small effect, ~0.5=medium effect, ~0.8=large effect) (20,21).
Cochran's Q (a=0.05) was employed to detect statistical heterogeneity and I² statistic to quantify the magnitude of statistical heterogeneity between studies where I² >50% represents moderate and I² >75% represents substantial heterogeneity across studies (22).To ascertain statistical stability and robustness of results, further meta-regression analysis was carried out based on pre-specified subgroups of interest where possible based on the evidence available i.e., the focus of intervention based on Chodosh framework (i.e., Tailoring, group, medical, feedback, and psychological emphasis) and intervention length of follow-up (< 6 months, 6 months or more).Publication bias was assessed using funnel plots where there were at least 10 studies in the metaanalysis.All analyses were performed using R software (metafor and dmetar packages) (23,24).
Patient-reported outcomes (distress, QoL, knowledge, behaviour change, self-efficacy) The pooled effect of diabetes self-management program interventions for older adults resulted in statistically significant improvements in the standardized mean differences in patientreported outcomes measures for behaviour change, diabetes knowledge and self-efficacy (-0.91 SMD; 95% CI -042, 1.41; p<0.00) (27, 29, 30, 33, 35-38, 40) (Figure 6).The most effective self-management program intervention strategy associated with the The pooled treatment effect of diabetes self-management program in older adults on glycated hemoglobin A1C (HbA1C).

Discussion
Diabetes self-management programs for older adults continue to evolve, particularly for older adults living with multimorbidity.Our updated review continues to demonstrate the value of selfmanagement programs on clinical and patient-reported outcomes by synthesizing the available evidence and identifying the most effective self-management approaches to use based on the type of outcome.Overall, diabetes self-management program interventions for older adults were found to reduce HbA1C by -0.32%, a statistically significant and clinically meaningful improvement, particularly as self-management programs are offered in conjunction with pharmacotherapy (9)(10)(11)13).Notably, providing self-management programs with the addition of feedback, as defined by Chodosh's framework, offered an improvement of 0.52%, which is similar to that of some pharmacotherapy agents.Self-management program interventions that offered feedback were also found to be most effective in improving patient-reported outcomes, specifically behaviour change (SMD 0.91; 95% CI 0.39, 1.43).Finally, self-management program interventions that were less than six months in duration were associated with improved clinical and patient-reported outcomes.This finding may be insightful for the design, implementation, scale up and sustainability of future self-management programs.

Strengths
The updated literature reflected all of the possible categories of Chodosh's framework for self-management programs for older adults, highlighting an evolution and distribution of selfmanagement approaches (13).The literature also reflected a broader reflection of outcomes, including patient-centred The pooled treatment effect of diabetes self-management programs in older adults on fasting blood glucose (mmol/L).
outcomes, such as behaviour change.Of note, many found some small but significant improvements that are noteworthy as self-management programs are often in conjunction with pharmacotherapy and comorbid conditions that require similar behaviors management, nutrition, and physical activity approaches.

Limitations
Our updated review included peer-reviewed literature published in English from November 2013 to July 2023.We recognize that literature may have been missed; however, we were able to apply the same search strategy to five databases yielding a large pool of citations.Unfortunately, concerning the representation of literature within the categories of Chodosh's framework, medical care in self-management programs continues to be minimally represented in the literature to date.We found the literature to be susceptible to bias as most of the studies were deemed to have an unclear risk of bias due to a lack of reporting (14).

Conclusion
Our review builds on the findings of our previous review (12) as it provides valuable insight into new literature that has emerged on this topic, specifically to understand the impact of specific selfmanagement programs on clinical and patient-reported outcomes for older adults living with diabetes.The findings help to better understand the growing body of literature regarding older adults receiving self-management education and support to meet their complex social, cognitive, medical, functional, and psychological needs (2-7).The findings of this review highlight the need for customization of self-management programs to optimize clinical and patient-centred outcomes, specifically noting that feedback strategies and programs of shorter duration (< six months) were most effective.Future research should explore the need for combination strategies (e.g.feedback and psychological emphasis) to address the complex needs of older adults living with diabetes and multimorbidity.Additionally, future research may also consider cost analyses of self-management programs in The pooled treatment effect of diabetes self-management programs in older adults on body mass index (BMI).The pooled treatment effect of diabetes self-management programs in older adults on (kg).The pooled treatment effect of diabetes self-management programs in older adults on patient-reported outcomes, specifically behaviour change, diabetes knowledge and self-efficacy.IPAQ, International Physical Activity Questionnaire; SCI-R, Self-Care Inventory-R; HEI, Healthy Eating Index; T2D-SCS, Type 2 Diabetes Self-Care Scale; DSMI-SF, Diabetes Self-Management Instrument Short Form; PDMS, Perceived Diabetes Self-Management Scale; SDSCA, Summary of Diabetes Self-Care Activities; SDSCA-GDC, Summary of Diabetes Self Care Activities-Diet; SDSCA-EX, Summary of Diabetes Self-Care Activities-Exercise; SDSCA-SMBG, Summary of Diabetes Self-Care Activities-Self Monitoring Blood Glucose; MARS-5, Medication Adherence Report Scale; MMAS, Morisky Medication Adherence Scale; DKN-A, Diabetes Knowledge Scale; RMDKQ, Revised Michigan Diabetes Knowledge Questionnaire; DMSE, Diabetes Self-Management Instrument; LSES, Lorig Self-efficacy Scale.
supporting older adults to remain out of the decrease the risks and impact of complications, and age in place.Just as no two people are the same, the findings of this updated review demonstrate that to improve different outcomes, customized selfmanagement strategies for older adults should be employed.

FIGURE 1 Study
FIGURE 1 Study flow diagram and selection, according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses.